Also, I found this earlier on reddit, if other people are googling and have the same problem:

 

Razer Nommo Pro not turning on?

Hello all,

This post is for the scrubs like me who bought a Nommo Pro, are way past warranty, and it is doing that dumb thing again where it just will NOT turn on.

It usually happens if you have a power outage, or have to unplug it to move it for some reason.

Some posts say things like leave it off and unplugged for a week. Or hold the power button for seven hours or whatever and I have done that before and it worked, but for whatever reason it didn't work this time.

So before I tell you my solution, DO NOT TRY THIS if you aren't comfortable tampering with electronics. Even if you are, I take no responsibility for what you do to your stuff, or if you injure yourself. This is just to tell you what I did to my stuff to get it working.

• I unplugged my system, opened the bottom of the subwoofer (which has the power supply inside) and first thing I noticed was a visible chongus capacitor.

• Checked it with my volt meter and it had about 1.1V of charge to it, super safe to discharge with a screwdriver. So I discharged it.

• I noticed for whatever reason it slowly started charging back up without plugging it back in, so it seems to be powered by some other caps somewhere deeper than I was willing to dig, or perhaps some part of the device has capacitance that shouldn't. So I discharged it a few more times over 2-3 mins just for fun.

• After that, I plugged it back in and it is working perfectly. No waiting required. (Cap had about 24V of charge after plugging it back in)

I hope this helps others fix razers poorly designed product.
(It sounds pretty good when/if it is actually working tho)